Thermoelectric safety device



April ZB, 1940. H. A. MANTZ 2,198,453

' THERIIOELECTRIQ SAFETY DEVICE:

Filed June 4. 1936 2 Sheets-Sheet 1 x93 6% ig- April 23, 1940. M TZ 2,198,453

:THERHOELECTRIC SAFETY DEVICE Filed June 4, 1936 2 Sheets-Sheet 2 Patented Apr. 23, 1940 THEBMOELECTRIO SAFETY DEVICE Harold A. Mantz, Milwaukee, Wis., assignor to Milwaukee Gas Specialty Company, Milwaukee, Wis., a corporation of Wisconsin Application June}, 1936, Serial No. 83,487

6 Claims.

My invention relates to an improvement in thermoelectric safety devices and the like.

While the device with which I shall describe I the present invention hereinafter in connection with the drawings is a particular type of thermoelectric safety valve and switch combination, it is to be understood that the present invention is not limited to use with any particular device but may be employed with all similar devices and elsewhere as suitable or desired.

For example, the present improvement may be used with the thermoelectric safety switch shown and described in the copendingapplication of John H. Thornbery and Harold A. Mantz, Serial No. 14,551, filed April 4, 1935, which has matured into Patent No. 2,132,057, issued October 4, 1938, as well as with other thermoelectric safety devices of similar character.

Thermoelectric safety devices which depend upon a weak voltage thermoelectric current for maintaining the flow of fuel for example to 'the main burner, and which operate to shut 011' the flow of fuel to such burner upon extinction of the pilot flame, require resetting means for resetting the device after the pilot flame has been extinguished. These resetting devices usually move the armature into contact with the pole faces of the electromagnet, and, simultaneously, the switch or other control device to position for setting up the supply of fuel to the main burner. If the switch or other control device is operated to set up the supply of fuel to the main burner when the resetting device is operated and irrespective of whether the pilot burner is lighted,

fuel may pass to the main burner and escape and I collect unburned. This unburned gas presents the danger of asphyxiation and possible explosion when a flame is applied to light the pilot burner.

V The object of the present invention is to provide means which will permit resetting and holding the armature in contact with the pole faces of the electromagnet without setting up the supply of fuel to the burner, and, particularly, means which will permit resetting and holding the armature in contact with the pole faces of the electromagnet without setting up the supply of fuel to the burner until the pilot flame has been relighted and a thermoelectric current set up to hold the armature in contact with the pole faces of the electromagnet. V

, The resetting device has a resetting button provided with a closure cap, and the supply of fuel is not set up to the burner until the pilot been relighted to set up a thermoelectric current to hold the armature in contact with the pole faces of the electromagnet and the closure cap has been applied into position covering the resetting button.

The fuel supply conduit for the main burner is controlled by an electrically operated valve, and it is one of the more specific objects of the present invention to provide contacts independent of the closure cap for controlling the circuit for this valve, one of these contacts being pressed into engagement with theother contact by the closure cap when said cap is in position enclosing the resetting element.

Another more specific object is to provide a pair of contacts for controlling the circuit for the electrically controlled valve or other device, with spring means for disengaging one of said contacts from the other contact-when the closure cap is removed, the closure cap pressing the disengageable contact into engagement with the other contact yieldingly through said spring means when the cap is in position enclosing the resetting element.

Another object is to provide a pair of fuel supply conduits, a thermoelectric device controlling the supply of fuel through both said conduits, means for resetting the thermoelectric device, and means for preventing the supply of fuel through one of said conduits during the resetting operation.

Another object is to provide a control valve, a control circuit having a switch therein, a thermoelectric device for' holding the valve open and the switch closed, means for resetting the thermoelectric device, and'means operable to open the control circuit during the resetting operation.

Further objects and advantages of the invention will be apparent from the following detailed description, taken in connection with the companying drawings, in which:

Figure 1 is a fragmentary and more or less diagrammatic viewshowing an embodiment of the present invention in a pilot burner and main burner gas supply system;

Figure 2 is a top plan view of a thermoelectric V safety valve and switch embodying the present invention;

Figure'3 is a vertical section on an. enlarged scale taken on the line 3--3 of Figure 2; and

Figure 4 is an elevational view, partially in section, looking from the right hand side in Figure 3.

' Referring to the drawings, the pipe l0, which may be the gas supply pipe for the main burner -per electromagnet enclosing hood '2.

erated valve I! of a type well known in the art.

The heater, appliance, or the like, is diagrammatically indicated at I4, and the main burner, which may be associated therewith in any suitable or preferred manner, may be controlled by v the valve II. This valve has electrically controlled mechanism connected into an electric circuit l5 which may be provided with a thermostat I 6 to be opened or closed in accordance with the temperature of the room heated by the heater, wherethe heater is a room heater, or the thermostat i8 may be arranged to be opened and closed in accordance with the temperature of the water in the tank, where the heater is a water heater, or otherwise as desired. The circuit I! may include the secondary winding of a transformer H, which may be connected to a suitable source of current.

Associated with the main burner in the usual or in any suitable or preferred manner, is a pilot burner it which is intended to remain lighted and which may be of any suitable construction. This pilot burner I 8 is supplied with fluid fuel by a tube is connected to the pipe ll ahead of the valve l2.

The thermoelectric safety valve and switch is indicated in its entirety at II and is shown interposed in thefuel supply tube is for the pilot burner l8. It comprises an intermediate valve housing 30, a lower switch casing II, and an up- These parts are held together by screws N which pass through openings in the bottom flange of the hood 32, down through openings in the housing 30, and have threaded engagement at their lower ends in threaded openings in the housing ii.

The intermediate valve casing ill is hollow and has a partition wall dividing the interior thereof into an inlet chamber'and an outlet chamber. The tapped inlet opening to the inlet chamber is adapted to receive the gas inlet pipe, and the tapped outlet opening from the outlet chamber is adapted to receive the gas outlet pipe which extends, for example, to'the pilot burner. The

valve casing 80 is thus interposed inthe fuel supply tube l9. Formed in the partition wall is a valve opening 34 surrounded by a valve seat, against which a valve 35 is resiliently pressed by a compression spring 36 when the electromagnet, indicated at 31, is deenergized. 4

The electromagnet 31 is disposed within the hood 32 and comprises a U-shaped magnet frame ll providedabout each of its legs with a coil ll. The magnet frame is held rigidly to a magnet mounting plate 40 by means of a bracket which is secured to the plate by screws, as shown. The plate III is rigidly secured to the hood .2 by a screw 4|. A name-plate may be provided as desired.

The magnet armature I is adapted to have engagement with the end portions of the U- shaped magnet 38. The armature is guided for reciprocatory movement within upright guide lugs on an armature guide 41 which is secured to the hood 3! by screws ll. One of said guide lugs is shown at 48 along the back of the armature 45, the other lug (not shown) being disposed along the front of the armature. The armature 45 has attached thereto, by upwardly extending bent-over portions, a'cradle which is connected to the upper end of the valve stem ll, preferably in a manner to provide limited universal connection.

The valve disc 35 is secured to the lower end of the stem 5! by a cradle 52 which has an inturned upper end which cooperates with a U- shaped retainer II engaging in a groove in the lower end of the stem BI. A limited universal connection is thus provided between the valve member II and the lower end of the stem II. The spring 38 is coiled about the stem II and conflned between the flanged margin of the cradle If and a valve stem washer II which has packing It disposed above it and in a recess in the armsture guide, so that gas cannot escape from the valve casing ll into the hood 8!. The under surface of the valve disc 3! has a gasket 88 clamped in a recess in the valve disc and between the disc and a washer by the resetting stem II, the upper reduced end of which is threaded into the valve disc I! as shown.

The resetting stem '0 extends downwardly through the valve opening 34 down, through an opening in the bottom of the valve casing 30, through switch casing ll, and out through an opening in the bottom of the switch casing. Packing is provided at If to seal the valve casing against gas leakage along the stem and into the switch casing. Fixed upon the lower end of the stem '0 is a resetting button 08 secured upon the stem by a retainer spring I and a screw I; To prevent unwarranted actuation of the button ll, a closure cap ll is threaded into the opening in the bottom of the switch casing and over the button ll completely to enclose the button. This cap It is removed to reset the valve, and the switch is reset by resetting the valve and replacing the cap ll.

The stem 60 isvslidable in an eyelet II which carries an insulating sleeve I. and holds a washer III to the lower end of thissleeve. A ring 12 engages in a groove in the stem II, and with the switch closed and the valve open, this ring is positioned above the upper end of the sleeve I a distance less than the spacing of the valve a above its seat. A contact disc I8 for bridging and connecting contact flngers 14 has a central opening provided with an eyelet with which a shoulder II on the sleeve 60 is adapted to cooperate in the downward movement of the sleeve ll to disengage the bridging contact II from the contacts II. The sleeve '0 is slidable in an insulating disc ll which seats upon the upper end of the tubular extension of the cap ll when this can is in position enclosing the resetting button. The contact flngers II have downturned ends (Figure 4) connected electrically to: terminal bushings "I8 and secured mechanically by said terminal bushings to an insulating terminal base ll secured over a lateral opening in the switch casing II. Spacers are provided at II, and the tubular. extensions of the bushings II are headed at I with a washer l2 interposed between the base I! andeach of these heads IL Terminal screws ll are threaded into each of the bushings II, and these screws are provided with terminal washers ll, A terminal cover II is suitably secured by means of serews'or the like (not shown) over the terminal screws OI and the outer ends of the terminal bushings. The bottom of the cover I! has openings provided with insulating grommets I through which the conductors, correspending, for example, with the conductors ll and I2 ofI'igureLareledintotheterminaicover II andconnected to the. respective terminal screws.

A coiled spring ll surrounds the insulating sleeve I! and is interposed between the contact disc 18, and specifically between the eyelet ll thereof and the insulating disc It. This spring fl holds the contact disc I3 yieldingly against the contact arm ll when the device is in the position shown in Figure 3, and at the same time permits the armature 45 to be pressed and held firmly against the 'ends of the legs of the magnet frame 38 without depending solely upon the yieldability of the contact arms I4. An insulating bushing 90, enlarged to surround the ring 12, is provided upon the stem 60, and a coiled spring 92 is interposed between a shoulder on this bushing'and a washer pressed against the packing 62.

- ,mocouple produces a thermoelectric current in the coils 39; This thermoelectric current produces a magnetic field in the magnet frame and armature of sufiicient strength so that when the armature is placed in contact with the ends of the-magnet frame by pushing the resetting button 63, the magnetic attraction holds the armature in raised position against the frame with a force greater than the force exerted by the spring means, thereby holding the contact disc 13 in contact with the contact arm 14 and the valve 35 in open position so long as the pilot flame is burning.

If the pilot flame goes out, the thermoelectric current through the electromagnet 31 ceases, and the springs 36 and 92 move the valve member 35 to closed position and, simultaneously, the contact disc 13 downwardly into open position out of engagement with the contact arms 14. The closing of the valve shuts oil the supply of gas to the pilot burner, and the opening of the switch opens'the circuit for the safety control valve I2, whereupon this valve moves to closed position to close off the supply of gas to the main burner- In the downward movement of the stem 68, the ring 12 engages the upper end of the eyelet 68 or insulating sleeve .69, and moves the same downwardly. Upon, this downward movement of the sleeve, the shoulder 15 thereof engages the eyelet'l5' or the contact disc 13 and moves the same downwardly into open position out of engagement with the contact arms" against the tension of the spring 88.

In resetting the device, the retainer ring I2 moves upwardly with the stem 60. -The bridging contact 73, however, is disengaged from the contacts 14 so longas the cap 66 is removed. When this cap is applied into position enclosing the resetting button 63, its upper end engages the insulating disc 16 and presses the contact 13 into engagement with the contacts 14 yieldingly through the spring 88. A gasket 95 is preferably provided between the terminal base I9 and the switch casing 3|, and gaskets are preferably provided at 96 and 91. i

- It isto be understood that the invention is not to be limitedto the embodiment illustrated and described, but iscapable of a wide variation of embodiments within the scope of the appended claims, and that changes may be made in the detailsof construction, arrangement, and relation of the parts. Furthermore, while the invention has been illustrated and described as employed in conjunction with a pilot light, it will be apparent that .the invention may also be used as a safety device in connection with other devices as, for example, the thermocouple could be subject to the heat of a main burner where it is desired that the gas valve be closed whenever the main burner goes out. Furthermore, the valve casing of the present device may be connected into other gas lines than the pilot supply line as shown, and the switch may control other circuits than a circuit for a remotely disposed electrically operated valve in the gas line for'the main burner.

I claim:

1. In combination, a control device comprising a valve housing, an upper housing secured to the top of said valve housing, a lower housing secured to the bottom of said valve housing, an electromagnet in the upper housing, a thermocouple connected to said electromagnet for energizing said electromagnet, an armature adapted to be held to said electromagnet upon energization thereof, a valve disposed in the valve housing and connected to said armature to be held .in open position when said electromagnet is energized by said thermocouple, a switch disposed in the lower housing and connected to said armature to be held in closed position when said electromagnet is energized by said thermocouple, -means for separating said armature from said electromagnet and opening said switch and closing the. valve when said electromagnet is deenergized, means for resetting the armature against said electromagnet, and means for opening said switch during the resetting operation.

2'. In a device of the character described, an electromagnet, an armature adapted to be held in attracted position by said electromagnet when said electromagnet is energized and movable to retracted position upon deenergization of said electromagnet, means for resetting said armature into attracted position, a closure cap for said resetting means, and a switch held closed by said armature and said closure cap when the armature is in attracted position and said closure cap is, in operative position, said switch being opened by movement of the armature to renected into an electric circuit, cooperating contact means, and yielding means biased between said cooperating contact means and said closure cap for holding said cooperating contact means in engagement with said first contact means when saidarmature is in attracted position and said closure cap in operative position and permitting separation of said. cooperating contact means from said first contact means when said armature moves to retracted position with said closure cap in operative position and upon removal of said closure cap from operative position withsaid armature in attracted position.

4. In a device of the character described, an electromagnet, an armature adapted to be held in attracted position by said electromagnet when said electromagnet is energized and movable to 4 i aromas contacts when said armature is in attracted position and said closure cap in operative position ,and permitting separation 01 said bridging contact from said first. contacts when said closure cap is removed from operative position and when said armature is moved to retracted position.

5. In a deviceof the character described, an electromagnet, an armature adapted to be held in attracted position by said electromagnet when said electromagnet is energized and movable to retracted position upon deenergization of said electromagnet, a resetting stem for resetting said armature to attracted position, a closure cap for said resetting stem, first contact means connected into an electric circuit, cooperating contact means, a sleeve member on said stem, a stop member seating upon said closure cap when said ,cap is in operative position, a spring biased between said stop member and said cooperating contact means, abutment means on said stem and cooperable with said sleeve member to separate said cooperating contact means from said first contact means by movement imparted to said stem upon movement of said armature to retracted position, and abutment means cooperating with said stop member for moving said cooperating contact means into engagement with said first contact means in actuating said stem to reset said armature to attracted position.

Q 6. In a device of the character described, a

housing having a valve chamber, an electromagnet chamber and a switch chamber, an electromagnet in the electromagnet chamber, an armature adapted to be held-in attracted position by said electromagnet when said electromagnet is e nergized and movable to retracted position upon deenergization 01' said electromagnet, a dividing wall between said valve and switch chambers, a resetting stem 'tor resetting said armature to attracted position and having reciprocatory movement in said wall, a valve member mounted on said stem and operable in said valve chamber, a closure cap for said resetting stem, switch means disposed in said switch chamber and held closed by said armature and said closure cap when the armature is in attracted position and said closure cap is in operative position, said switch means being opened by movement of the armature to retracted position with the closure cap in place and by removal of said closure cap from operative position with said armature in attracted position, packing. means sealing the passage of the resetting stem through the dividing wall between said valve and switch chambers, and yielding means biased between said packing means and an element of said switch means.

' mom A. mm. 

